title: A case-control study on platelet reactivity in patients with coronary stent thrombosis.
abstract: BACKGROUND
  The pathophysiology of stent thrombosis (ST) has evolved from the identification of single causative factors to a complex multifactorial model.
  
  
  OBJECTIVE
  The aim of the present study was to investigate whether patients with a history of ST exhibit heightened platelet reactivity to clopidogrel and aspirin.
  
  
  METHODS
  Pretreatment and on-treatment platelet reactivity to clopidogrel and aspirin, as well as dual antiplatelet therapy resistance, was determined in 84 patients with a history of definite ST (cases: 41 early ST; 43 late ST) and in 103 control patients with a previously implanted coronary stent but no ST after the index procedure. Platelet function was evaluated with optical aggregometry, the VerifyNow P2Y12 and aspirin assays, the PFA-100 Innovance P2Y* cartridge, the flow cytometric vasodilator-stimulated phosphoprotein assay and urine 11-dehydrothromboxane B(2) measurement before and after the administration of a 600-mg loading dose of clopidogrel and 100 mg of aspirin. The study was registered at ClinicalTrials.gov, number NCT01012544.
  
  
  RESULTS
  Patients with a history of early ST clearly demonstrated higher on-clopidogrel platelet reactivity than controls. Patients with both early and late ST exhibited heightened on-aspirin platelet reactivity status, and dual antiplatelet therapy resistance was more frequent.
  
  
  CONCLUSIONS
  Patients with a history of early ST exhibit a poor response to clopidogrel. Furthermore, both early and late ST are strongly and independently associated with heightened on-aspirin platelet reactivity, and dual antiplatelet therapy resistance is more frequent.
authors.affiliation: St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, The Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: Bouman
authors.forename: J W
authors.initials: JW
authors.lastname: van Werkum
authors.forename: N J
authors.initials: NJ
authors.lastname: Breet
authors.forename: H
authors.initials: H
authors.lastname: ten Cate
authors.forename: C M
authors.initials: CM
authors.lastname: Hackeng
authors.forename: J M
authors.initials: JM
authors.lastname: ten Berg
mesh_terms: D000368:Aged; D001241:Aspirin / Q000494:pharmacology*; D001792:Blood Platelets / Q000166:cytology*; D016022:Case-Control Studies; D000077144:Clopidogrel; D003328:Coronary Thrombosis / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010979:Platelet Function Tests; D015607:Stents; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D014665:Vasodilator Agents; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin